The various embodiments described herein relate to a mail processing system and a method of loading articles onto a transport system.
Each day the United States Postal Service (USPS) processes articles for delivery to millions of individual domestic addresses. As used throughout the application, articles refer to mail items, magazines, books and other such flat items. Before mail carriers begin to walk through or drive through their delivery routes, a mail processing system at a USPS processing site sorts all articles for the carriers and packages the sorted articles for each domestic address. A carrier's responsibility includes putting all of these articles into an appropriate sequence for efficient delivery to the domestic addresses.
The mail processing system is highly automated to handle the amount of daily articles. It includes a delivery point packaging (DPP) system that, for example, separates the articles, reads their destination addresses and groups the articles based upon their respective destination addresses. One example of a DPP system includes an arrangement of a multitude of individual slots for individual articles. A transport system having containers with pockets transports the articles along a track system to the slots. Feeders or loaders insert the articles into the transport system at loading points. At this point, the destination address of an article is known and the transport system transports the article along a delivery path to a slot that is pre-assigned to the destination address of that article.
A general aspect of a mail processing system is to operate it as efficient and reliable as possible, but at the same time without causing any or too much damage to the articles. One area in the mail processing system that influences efficiency, reliability and potential damage are the loading points. For example, to achieve a high throughput a loader needs to insert an article into a pocket as fast as possible, and to load as many pockets as possible. Hence, the pockets on the transport system should be densely packed and have openings that are only slightly larger than the thickness of an article, but still wide enough to ensure safe and reliable loading.
Known techniques for loading the articles include, for example, 1) stopping the transport system, 2) feeding an article while the transport system moves and passes the loader, or 3) using a loader having a swivel arm that follows the moving transport system. However, these techniques require the transport system to generate high acceleration forces after each stop (1), the loader to insert the article with a high speed, which increases the risk of damage to the article, while the pocket opening needs to be relatively large (2), or the pocket openings need to be relatively large to compensate for any angle aberrations.